1. Field of the Invention
The present invention relates to a recording and/or reproducing apparatus for recording and/or reproducing signals on and/or from a recording medium and, more particularly, to a recording and/or reproducing apparatus in which reproducing characteristics are improved particularly in a slow-speed reproducing mode in which the recorded signals are reproduced from the recording medium running at an average speed lower than in the recording mode.
2. Description of the Related Art
Rotary head type magnetic recording/reproducing apparatuses of the type mentioned above have a slow-speed reproducing mode in which signals are reproduced from a recording medium, e.g., a magnetic tape, running at an average speed lower than the running speed of the medium in the recording mode. In general, there are two types of methods which realize such a slow-speed reproducing mode. In one of these methods, the desired low tape running speed is attained by intermittently feeding the tape, i.e., by alternately employing a period in which the tape is fed at the same speed as that in the recording mode and a period in which the tape is held still. The other method, generally referred to as the "dynamic tracking mode", employs an actuator to a free end of which is fixed a head carried by a rotary drum. The actuator displaces the head in a direction which intersects the direction of rotation of the rotary drum, so that reproduction is conducted with high degree of tacking precision from the tape which runs at a constant speed lower than the speed in the recording mode.
With the first-mentioned slow-speed reproducing mode, however, it is difficult to pick-up signals from the whole track width throughout the period of the slow-speed reproduction, because of a lack of precision in the tape feed control. Consequently, noise is produced during slow-speed reproduction or, alternatively, an additional head for exclusive use in slow-speed reproduction has to be employed.
Furthermore, in a reverse slow-speed reproduction mode in which the tape is fed in a direction reverse to that for recording, reproduction cannot be conducted satisfactorily even when an exclusive slow-speed reproducing head is used, because the head trace angle largely differs from the track angle.
The second-mentioned slow-speed reproducing method, i.e., the "dynamic tracking", requires complicated mechanisms and control in order to achieve the dynamic tracking function, resulting in increased costs of production. In addition, it is not easy to precisely control the feeding of the tape at the reduced speed.
The current trend towards the use of digital signals applies also to the field of VTRS, and digital VTRs have been proposed in line with this trend. In such a digital VTR, as shown in FIGS. 1(a) and 1(b), image signals for one frame are divided into plural blocks. Each block, generally referred to as sync block, is composed of image data, a sync signal for enabling digital demodulation, and an ID signal which comprises position information indicative of the position of the block in the frame. The sync blocks are then recorded in a tape in a manner shown in FIG. 1(c). Although not illustrated in detail in FIGS. 1(a) and 1(b), the audio signal has a construction similar to that of the video signal.
In most cases, reproduction is conducted by reproducing the data of the blocks through digital demodulation, recombining the reproduced data in a frame memory based on the ID signals to form the image information on a frame basis, and then outputting the information of the successive frames.
In the digital VTR, the image is output through a memory, rather than by directly forming output signals in real time from the RF signals reproduced through the head tracking operation.
The present inventors have found that this feature of the digital VTR allows the operation of a superior and novel slow-speed reproducing function different from those of the known arts.